Rotors of gas turbine engines such as turbine rotors, compressor impeller rotors, rotors with separate or with integral blades, etc., typically have a rotor disc (whether integral with or separately manufactured from the blades) with turned surfaces. Such turned surfaces, and particularly those having a curved cross-sectional profiles, are typically machined by a turning method where the rotating rotor disc is put into contact with a stationary or translating point tool grinding the surface to the desired profile.
Improvements in fuel efficiency lead to gas turbine engines being run at higher temperatures. As such, harder materials are used to form the parts of the gas turbine engines. Such materials having high temperature strength and hardness are more difficult to machine. The resistance of these materials can be such as to produce, for example, excessive wear of the point tools, breakage of the point tool tips, chipping of the point tools, reduced machining speeds, and/or damaged workpiece surfaces.